Process of coloring paper



Aug. 17, 1937. P. DREWSEN PROCESS OF COLORING PAPER Filed May 6, 1935 INVENTOR PIERRE DR EWSEN ATTORNEYS Patent ed Aug. 11, 193-,- 2,089,949

UNITED'STATES PATENT OFFICE PROCESS OF COLORING PAPER Pierre Drewsen, Sandusky, Ohio, assignor to The Hinde & Dauch Paper Company, Sandusky, Ohio, a corporation of Ohio Application May 6, 1935, Serial No. 20,102 7 Claims. (Cl. 101-153) The invention relates to methods of coloring nish a sheet of colored paper which has a surpaper and producing colored design efiects on the face different from the ordinary grade of paper, surface of the paper. It is the object of the infor example, a surface with gloss or sparkle. Anvention to obtain a process which while appliother disadvantage is the relative inability of a cable to paperin general, is particularly adapted paper mill to color paper on one side only, as is for the coloring of paper to be used in the manuoften desired, as for instance, for display purfacture of corrugated paper and solid fiber boxes, poses, t is t t a calender Coloring s merchandise display stands, display materials and qu y done in P p mills, but when a Water the like. To this end the invention consists in a Water Solution s pp 170 a Sheet going 10 the novel process as hereinafter set forth. through the calender stacks, under-the pressure 10 In the drawing: exerted by the heavy stack of rolls, the tendency vFig. 1 is a diagram illustratingan apparatus is to give the sheet a water finish, that is to say, adapted for the carrying out of my improved a glazed efiect, which for some purposes is not method; a desirable. The principal objections to paper mill 10 Fig. 2 is an enlarged view of Fig.1; coloring, then, are the limited efiects obtainable,

Fig. 3 is a perspective vi thereof, and the relative inability of the mill to furnish In the present state of the art there are' a paper in small qu t of t proper l or number. of methods of coloring paper, and of prodesign without prohibitive loss of time for washducing colored design efiects, and of coating p and shutdowns, and Without impounding paper. For ordinary purposes, paperiscoloredin k ng capital in slow moving r unprofitable 20 the paper mill. In this process aniline dyestuffs linesof' odd sizes. Generally sp i n or colored pigments are added to the paper pulp ffects in color are not obtainable on a paper in the beater, and after adding the necessary machine rosin size and alum, the stock is jordanned and Another method of coloring or t rw hang- I formed into a sheet on the-paper machine. There ing the u a of P p is the Well known coat? 5 are a number of disadvantages in this method. ing D In this P P p r is P e In the first place, particularly where deep color through a machine n Which a liquid mixture of effects are desired, a considerable portion of the Casein, China y and aniline dy Stuffs s al coloring material used is l st in th il ilm t, plied to one or both surfaces of the sheet, after When-changing from one color to another, parwhich it is dried, and then calendered. The ma- 30 ticularly from a darker'to a less dark shade, it is chines o i p p e is o o s fo anoften necessary to shut down the mill and thorp ying the liquid m after which the liquid oughly wash all chests, heaters, pipe lines, vats, mixture s spread ve the s e of e p p etc. The time, labor and overhead elements inby m ans of am l's ha u s- Equ p of volved make the production of small uantitie this a a t sp ally th h m a s, t of colored paper economically impossible in most melchine rooms, ng Poems, Calender 'O mS, cases. Another serious-disadvantage of coloring are large, and the p on requires papcr in a paper mill is the problem of trim. Each sidelable p In general, the Coating P100955 paper machine has a maximum width of'sheet aims rather to produce a fine surface for print- 40 which it may produce. If, for example, an order the Coloring being more 0 less incidental 40 is received for green liner board which t b and limited to delicate tints, heavy or deep colors say soineh wid t b run on a paper machine. being largely avoided. The coating process is used which trims 80 inches, it is necessary to make a la y r magazine cover stocks, an ta sheet of green paper 80. inches wide, and then trim es of book i p out a roll or rolls inches wide, leavingrolis of Colored design effects y be pr c d by 5 green paper 30 inches wide. These, having no pr n n presses and printing inks- In en ral. immediate utility, are placed in storage, where there are three yp of printing; the raised tthey may stay indefinitely. It is obvious that ter p in Which the impression is ad by P .under present operating conditions, it would ot tions of the surface of the printing element which 50 be long before any mill attempting to supply is elevated above the surface of the roller or 50 colored boxes or other grades of colored paper plate; ofiset printing, in which the efiect is prowould soon be faced with a serious accumulation duced by the contact of a flat surface with the of odd sized material which would impound workpaper, the ink being delivered to the fiat suring capital. Another disadvantage of paper mill face first, and finally, there is the so-called incoloring is the practical inability of amill to furtaglio process in which the impression is made 55 by an engraved roller. In this latter process, the

from the copper roller, and thereby receives the color impression. In the intaglio process, either fiat colors may be imparted to the paper surface, or designs of various sorts may be printed.

Sometimes two or. more copper rollers are used,.

each one of which employs a different color, and each of which registers with the others, so that a multi-colored design is produced in the paper. For the purpose of this application, however, we are not concerned with multi-colored effects.

The intalgio process is not particularly satisfactory for printing or coloring or coating liner board. Liner board is made largely from waste paper material, and the rolls of liner board, as received from the paper mill, contain considerable quantities of dust or other impurities which concentrate'in the ink fountain, and these dust particles gradually work their way up under the doctor blade which results in streaking the paper and spoiling the product. per roller with the engraving on it is a relatively delicate surface, there is no practical method of cleaning out the dirt from under the doctor blade without injuring the copper surface. If the machine is shut down, there is an interruption of production, and the spoilage of a considerable quantity of paper, and even after the doctor blade is cleaned out, no solution of this problem is offered, because the doctor blade will immediately become fouled again.

I have found that the defects above described can be overcome by removing the doctor blade and permitting the coloring material to be carried up by the fountain roller to the surface of the paper strip in advance of the passage of the same into contact with the knurled or engraved surface. This has the effect of flooding the surface with coloring material, after which the surplus material is squeezed out, leaving only that which is in the depressions in the engraved roller for deposit on the surface of the paper together with a lighter color background on the intermediate unengraved portions. I have discovered that with this method dust or impurities carried by the paper will not accumulate or cause any streaking or smearing of the colored surface. It is, however, desirable to modify the apparatus from the construction employing a doctor blade, as hereinafter set forth.

As illustrated in Fig. 1, A is the roll of paper to be colored from which the strip passes around friction bars B to place thereon the desired ten sion, after which it passes over a pair of rollers 0 intermediate which is arranged a steam jet tube D directed against the under surface of the strip. From the'roller C the strip passes around a roller E having a plane, unyielding surface, preferably of steel, then around a roller F, the surface of which is formed of rubber or other resilient material and which is pressed in contact with a roller G which has the engraved or serrated surface. The latter .roller has a portion of its surface immersed in the color fountain H and when rotating and moving the paper web Inasmuch as the copficult to afterwards unroll.

will carry the coloring material up on one side into the trough formed between this roller and the roller F. This will flood the surface of the paper which is passing around the roller F and will also fill all of the depressions in the engraved surface. Thus as the web passes between the rollers F and G, all of the surplus colored mavaried by means of a roller J which is adjustable around the periphery of the drum I as indicated by the arrows in dotted lines. After passing around the roller J the web isdelivered to the rewinder, not shown,

The paper web in passing around the resilient surface of the roller F is held in close sealing contact therewith so as to prevent the runningof the coloring material on to the reverse side of the paper. However, as illustrated in Fig. 3, the portions of the roller F which extend beyond the edges of the paper strip will come in contact with the coloring material carried by the roller G which will be transferred thereto and carried upward. This might result in smearing the reverse surface of the paper as it passes around the roller E and to avoid such effect I preferably blow compressed air into the trough between the rollers F and E and direct it outward from the edges of the paper strip, as shown at H and H in Fig. 3. This will clear the surface of the roller F from the coloring material in the vicinity of the edges of the sheet, not only preventing it from smearing the reverse side of the paper strip but also avoiding any danger of the sticking of the edges of the strip when rewound, which might render it dif- However, the process may be carried out without the use of these air jets.

When an engraved roller is used on whicha pattern is engraved, the effect of operating in this manner is to produce a two-color effect. The unengraved portions of the copper roller give a light coloring effect, and the deeper engraved portions give a deeper effect of color. After the paper is colored, it is then dried by passing the web over a cylindrical drier or series of dryers, and in this operation it is important that the colored surface does not come in contact with any roller or other object until it is dry, otherwise the color will smear. Having-accomplished the drying, the paper is then rewound into a roll.

It is possible to employ a multi-color effect in this process by passing the paper with one color application through a similar set of rollers, using -a pattern which registers with the first, and

for a similar solid color effect,'a water solution of an aniline dye to which a solution of casein has been added will produce a plain effect. For design effects, it has been found desirable to thicken the color solution by adding some water soluble material, such as casein, starch or animal glue, with or without clay, lithopone, zinc pigments, titanium oxide or other similar solid materials, depending on the surface efiects desired.

To produce proper coloring, the absorbent character of the paper surface and the penetrating character ofthe coloring matter must be regulated with respect to each other. I-have found that the subjection of the paper surface to a steam bath places it in condition to receive more uniformly the coloring material. -With certain papers and with certain water soluble aniline dyes it may be desirable to mix with the coloring material alcohol or some other substance for increasing the penetrating power. Again, for other uses it may be desirable to increase the viscosity of the coloring material so as to lessen the penetrating power, and again for certain uses an adhesive constituent such as casein may be advantageously added to the coloring matter. By such regulation different effects may be produced as desired.

' What I claim as my invention is:

1.- A process of coloring paper comprising. the feeding 'of a paper strip between a knurled roller and a roller having a resilient surface flooding the surface of the knurled roller and the paper surface adjacent thereto with coloring material whereby in the movement of the paper between said rollers surplus coloring material is-squeezed out and the color in the indentations of the roller is deposited on the surface of the paper and after separating from the paper removing all coloring material from the portions of the resilient roller which are adjacent to the edges of the paper subsequently contacting with the roller. 1

2. The process of coloring paper comprising the feeding of a paper strip around a segment of av roller having a resilient surface and between said roller and a knurled or engraved roller, flooding the surface of said knurled roller and the paper adjacent thereto with coloring material where-' by in the of the paper strip between said roller surplus coloring material will be squeezed out and the coloring material in the indentations of the knurled or engraved roller will be depositedon the surface of the paper and after separating from the paper removing all coloring material from the portions of the resilient roller which are adjacent to the edges of the paper subsequently contacting with the roller.

3. The process of coloring paper comprising the feeding of a paper strip between a knurled or engraved roller and a roller having a resilient surface, flooding the surface of the knurled roller and the surface of the paper adjacent thereto with coloring material whereby in the passing of the strip between said rollers surplus colorin material is squeezed out and coloring material in the indentations of the roller is transferred to the surface of the paper, and blowing'thecoloring material adhering to the portions of the resilient roller adjacent to the edge of the paper to remove the same from further contact with the paper.

4. In a process of coloring paper by feeding the same in contact with a knurled or engraved roller flooded with coloring material, the step of adjusting in relation to each other the absorptive property of the paper surface and the penetrating quality of the coloring material.

5. In a process of coloring paper by feeding the same in contact with a knurled or engraved roller flooded with coloring material, the step of humidifying the surface of the paper in advance of the contact of the same with the coloring material.

6. In a process of coloring paper by feeding the same in contact with a knurled or engraved roller flooded with coloring material, the step of treating the surface of the paper with steam in advance of contacting the same with the coloring material.

7. In a process of coloring paper by feedin the same in contact with a knurled or engraved roller flooded with coloring material, the step of adjusting the viscosityand penetrating charac-. 

